Self hardening bituminous cement and process of making the same



Patented July 14, 1931 UNITED STATES PATENT? OFFICE DOZIE-R FINLEY, OF BERKELEY, CALIFORNIA, ASSIGNGR TO THE PAFJAFFINE COM- PANIES, INC., OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWARE SELF HARDENING BITUMINOUS CEMENT AND PROCESSOF MAKING THE SAME No Drawing.

The invention relates to plastic materials in which one of the major constituents is a bitumen, and more particularly to bituminous plastics which harden in use.

One of the objects of the invention is the production of a plastic mass adapted. to be inserted in a cavity of considerable volume and which will harden therein by internal action.

Another object of the invention is the production of a plastic mass of special use as a sealing material which is both waterrepelilent and waterproof.

Another object of the invention is the production of a cement of special value as a jointing compound for vitrified salt glazed claypipe and for use as a sealing materla-l on the terminals of metal conduits, and for other similar uses, and which may be prepared and applied at the point of use without heating.

Other objects of the invention, together with the foregoing, Will be set forth in the following description of the preferred emi, bodiment of the invention. It is understood that I do not limit myself to the showing made by the said description, as I may.

adopt variations of the preferred embodiment within the scope of the invention, as set forth in the claim.

So far as known, the previous attempts to make bituminous compositions of a plastic nature have contemplated the establishment of an equilibrium between the bituminous components and such other components as may be miscible in the bituminous materials. The whole composition being in equilibrium from the time of manufacture to the time of use, hardening or setting does not take place thru an internal action in the composition, but as a result of the abstraction or alteration of one of the components. Usually the hardening is accomplished thru the evaporation of volatile solution. To liquefy solid asphalt at ordinary temperatures, 1t

Application filed December 4, 1926; Serial No. 152,725.

is necessary to cut it with approximately an equal volume of a solvent. For example, four and a quarter pounds of hard asphalt and two quarts of benzole may be combined to form a liquid paint. They may be com bined either by heating the asphalt and mixing the benzole therewith, or by breaking the asphalt into moderately small pieces and agitating 'itinto the. benzole until thou oughly dissolved: If, however, four pounds of asphalt is'mixed with three-quarters of a pint of benZole, the resultant mixture when it becomes homogeneous, i. e., in equilibrium throughout will be found to be, not a liquid, but a semisolid asphalt. In other words, the benzole in this instance has only servedto soften the. original hard asphalt.

If the asphalt and benzole are not in equilibrium, there results a very interesting condition. If the asphalt has been pulverized into granules or grains ranging from the size of BB shot to No. 8 shot, and the benzole is poured over it, the resultantmass, for a period of several hours, is not the semisolid of the homogeneous state, nor is it an actual liquid, but merely wet particles which move easily over each other. In this condition, the mass can be worked or stirred, and may be iitly characterized by the word magma. The magma phase is of short duration; the benzole being absorbed into the solid granules of asphalt at a fairly rapid rate and undergoing a sort of liquiddissolvingdn-a-solid process, until ultimately, equilibrium is attained (assuming no evaporation of the benzole takes place), at which time the product is a semisolid mass first above described, i. e., four pounds of asphalt and three-quarters of a pint of benzole. V V

Considering the components of this magma, I am led tocertain conclusions which are confirmed in practice. The hardest asphalt and the least quantity of benz ole, or rather solvent, will give the firmest consistency in the final product, after equilibrium is established.

To use the least quantity of the solvent and still to secure a final product of maximum density, a graded aggregate of asphalt should be used; that is, the asphalt granules should range from pea size, down to dust, each smaller size filling the voids between larger ones. In this case, the dust particles will be quickly dissolved by the solvent, thus diminishing or destroying the magma producing effect of the solvent. In other words, with a well graded void-filled aggregate of asphalt, the magma phase of the mixture is of brief duration.

In order to secure the advantages of such a void-filled aggregate, and yet avoid too short a duration of the magma phase, the finer mesh asphaltic particles may be omitted, and replaced by particles of insoluble mineral matter, such as sand and crushed stone dust. This secures all the advantages of slow setting, or a long period in the magma phase, and yet permits of the use of relatively small quantities of the solvent.

By charging the solvent itself with the maximum amount of the solid phase material, the amount of solvent needed may be diminished. A mixture of one-half pint of solvent and one-quarter pound of hard' asphalt will make practically three-quarters of a pint of solution which has a viscosity differing very slightly from that of the original solvent. Such a mixture can be used in wetting the solid phase of my bituminous cements almost Without any increase of quantity. By the employment of this method the amount of actual solvent can be reduced toabout two-thirds of that which would otherwise be needed. Still another method of limiting the amount of solvent is available. This consists in making the solvent somewhat plastic without materially reducing its resistance to distortion. Taking the illustration which we have been using throughout, the solvent may be changed from the original all benzole, or all base liquid, and further changed from the asphaltsolvent wetting fluid to a composition quantitatively represented as follows:

1. One eighth of a pound of hard asphalt dissolved in one-quarter of a pint of solvent, mixed with 2. Three-sixteenths of a pound of melted parafiine wax mixed with three-sixteenths of a pint of solvent.

This material is a black, semisolid, soft, waxlike material which will shear with little or no resistance. It will be noted that it contains over a little over half (58%) of the quantity of solvent contained in the formula first mentioned. The actual amount may be reduced in practice so that not more than half the amount initially suggested is used. This is because a remarkable phenomenon takes place when the plastic solvent is mixed solid phase of this material.

such as crushed rock dust.

with the mixture of granular asphalt and mineral fillers. The plastic solvent now no longer primarily dissolvingly wets the dry materials, but tends at first to distribute itself among that material much as a grease would do. WVhen final mixing is effected just before actual use the product is more plastic, more easily mixed, easier to force into small openings, will wet contiguous surfaces more effectively (whence it secures a better bond) and, generally speaking, becomes harder on setting. Because a more-plastic mass results, it is possible to reduce the amount where this improved wetting material is used, so that, instead of three-quarters of a pint of solvent, it is possible to use only elevensixteenths of a pint, or even slightly less, and still the mass will be just as plastic and just as easy to mix as if three-quarters of a pint of pure solvent Were used.

It is found too that the paraffine gives a good quality to the mixture Where water resistance is required, that is to say, it makes the material more waterproof, because paralfine is a natural water repellent material. I have found however that if the paraffine is melted and heated with five percent of its weight of aluminum stearate until the latter is dissolved in the paralfine, the waterproofing quality is greatly enhanced, as aluminum stearate is one of the most water repellent substances known.

It is also possible to effect variations in the For instance, in place of hard asphalt, which here is intended to represent a substantially pure asphalt, the asphalt may be mixed with a considerable portion of inert or mineral matter, In this way the cost of the asphaltic component is reduced, but at the expense of its solvent absorbing capacity, for it is readily seen that a mixture of 60 parts asphalt and l0 pounds rock dust will absorb only 60% as much solvent as one having 100 parts of asphalt.

Variation is possible in the aggregate which is incorporated in the compound, and which may be mineral or of vegetable origin such as rice hulls. For convenience a certain amount of soapstone is used with the asphalt to prevent the granules of asphalt from adhering to each other. But I have found there is a great advantage in using infusorial, or diatomaceous, earth as a mineral constituent of this bituminous cement. Infusorial earth has a very great capacity for absorbing oils or semisolid asphaltic materials. Consequently the infusorial earth used in the formulae given below is of great assistance in absorbing portions of the asphalt cut by the solvent and thereby additional hardness results.

While I have mentioned only hard asphalt in the discussion of this invention, it is to be remembered that hard asphalt may be either natural asphalt such as gilsonite, or Trinidad asphalt; or it may be refined from petroleum. If the latter, it may be either oxidized (blown) asphalt, or steam run. All of these asphalts are applicable to the carrying out of my invention. But I do not confine myself to asphalts, as coal tar pitch, stearine pitch, pine tar pitch or even rosin may be used either alone or in combination with each other or with asphalt.

Benzole is mentioned as a solvent in the above discussion,but benzolewould not carry out the purposes of my invention in many cases so Well as some other solvents. Benzole evaporates so rapidly that its use may be attended by an unduly rapid stiffening of the product, as well as by a too thorough hardening with the progress of time. YVhile I nay use benzole, I prefer to use solvent naphtha, coal oil, turpentine substitute, turpentine creosote, gasoline, fuel distillate, carbon tetrachloride, dichlorethylene, trichlorethylene, and like chlorinated or other non-inflammable derivatives. The solvent'need not be a perfect solvent for the bitumen. It may be merely a softening agent.

So far as inert constituents are concerned. I have employed sand, powdered soapstone and infusorial earth. I may employ clay, crushed limestone, crushed slate, brick dust, silica, or even rice hulls.

I have found further that a fibrous component is of value in the composition, and I may use anysuitable material of fibrous character. I prefer to use asbestos fibre, the particular grade being known in the trade as O-O-106, which is a papermaking fiber, but other grades may be used. Fiber of wool, cotton, burlap and the like may also be used.

Preferred procedure The solid phase of the composition is made up thus 330 pounds California B asphalt 330 pounds hard blown California aspha t 100 pounds pulverized soapstone (this includes that used in crushing the asphalt) pounds infusorial earth F300 pounds sand, 20 mesh to 40 mesh 60 pounds asb stos fiber. 0*0-10-6 Making in all 1200 pounds.

The asphalts are melted and the mineral ingredients stirred therein to make a masticlike material, which when cooled may be crushed and screened thru a 6 mesh screen, all fines remaining in-the product. 7 The paste phase is th-us madeup-r (a). 2 -4 poun s hard blown cali am a asphalt 24.4 pounds gilsonite 2. 9- gallons turpentine. s bstitute- 10. 7 *"allons coa o' Ma k inz aliout 19 gallons.

73. 1 pounds 128 F. melting point parafli'ne' wax 6, pounds aluminum stearate,

lie-at together until aluminum stearate is dis olved in the wax, cool to about 260 F. and add 9-.7. gallons of coal oil making in all about 19 gallons. Mix (a) amt (b) together.

When it is desired to use the bituminous mixing immediately follows the first and may be effected in a machine; of the character of the common kitchen meat grinder, if for small" quantities. In large quantities the revolving bowl mixer may be used by'the addition of more heavy iron balls to knead together the solid; and the paste.

Instead of making the paste phase as just described, (a). and (b) may be mixed together with about 272, pounds. of finely crushed mineral matter preferably finely ground shale, which will increase its volume to about 55 gallons but which will not materially reduce its fluidity or plasticity. The paste phase thus loadedwith inineral' matter can be used-withthe solid phase in a very slightly increased quantity, say instead of 39 gallons, use 44 gallons...

It is understood however, that other proportions ofsolid and paste phases may be used together. (atone/rally speaking a lesser amount of paste being used when a stiffer product is used. In this wiseI have successfully used as little as half the quantities of the, paste phase called for in the two paragraphs last above Written. The product was stiff and showed many unfilled voids, which however would not unfit it for certain uses.

As still another alternate method of procedure, I may take the ingredients of the solid phase as above named, and pulverize the asphalts by any convenient means such as a hammer crusher. In order to prevent caking of the asphalt particles, about three per cent by Weight of finely powdered soapstone may be fed to the crusher with the asphalt. The crushed product is graded and all that passes thru a 6 mesh screen and is retained on a 20 mesh screen is used. I then mechanically mix together all the ingredients of the solid phase in the respective amounts above enumerated without employing heatr To this mixture of the ingredients of the solid phase, the paste phase may be added in the amounts above specified, and mixed therewith in the manner described, when it will be found that the product will have all of the desirable qualities, and may be adapted to the same uses, which characterize the product made by the preferred method.

lVhen the mixing operation is complete the I product should be a dense, black plastic composition which can be readily forced into cracks in cement floors or pavements, may be pushed into, and caulked in, the bells of vitrified salt glazed sewer pipe, or against the exterior of walls to resist water pressure. The material may be applied by trowel, by caulking tools or by a tool of the character of a grease gun. It will remain plastic for several hours and then gradually harden without shrinkage, by an internal action which is quite independent of any evaporation of the solvent or softening agent which may occur.

I claim:

A cement comprising the product resulting from the combination of the following substances in substantially the proportions stated:

660 pounds asphalt 60 pounds asbestos fiber 100 pounds pulverized soapstone 80 pounds infusorial earth 300 pounds sand and with a softening agent comprising a mixture of (a) and (b) r 48.8 pounds asphalt 7 3.1 pounds parafline wax 3.6 pounds aluminum stearate 9.? gallons coal oil In testimony whereof, I have hereunto set my hand.

DOZIER FINLEY. 

